煤炭燃烧过程中N2O消除反应机理的密度泛函理论研究

用密度泛函理论B3LYP方法对煤炭燃烧过程中N₂O的消除反应进行研究。选用6-311++G**和aug-cc-pVTZ基组,优化了反应通道上反应物、过渡态和产物的几何构型。预测了它们的热力学性质(总能量、焓、熵和吉布斯自由能)及其随温度的变化。预测N₂O+CO反应的活化能为200 kJ·mol^-1,与实验值193±8 kJ·mol^-1较一致。计算了500~1 800 K 温度范围的反应速率常数。在N₂O的分解中,N₂O与H和CN自由基的反应为动力学优先进行的反应,其活化能为50~55 kJ·mol^-1。在B3LYP/aug-cc-pVTZ level水平下,N₂O+CN反应是热力学最有利的自发反应,其吉布斯自由能变化为-407 kJ·mol^-1。     

复盐法制备无水氯化镁的热解机理及动力学研究

The complex compound (MgCl₂·C₆H₅NH₂·HCl·6H2O) was prepared by reaction of C₆H₅NH₂·HCl with MgCl₂·6H₂O. Reaction mechanism and kinetics of the compounds decomposition were studied by means of the TG-DTA-MS coupling technique and the TG-DTA technique. The results show that there are four steps in the complex′s thermal decomposition, the first two steps correspond to the loss of six crystal waters and the last two steps loss one Aniline hydrochloride. The first three steps belong to the R2 mechanism with 2-dimentional phase boundary reaction as the control step, and the last step belongs to the D3 with 3-dimensional diffusion (sphere Jander equ.) as the control step. The apparent active energy of four steps are, 127.4 kJ·mol^-1, 124.8 kJ·mol^-1, 142.3 kJ·mol^-1 and 329.0 kJ·mol^-1, respectively and the frequency factor are 1.28 × 10¹⁸ s^-1, 7.94 × 10¹⁵ s^-1, 5.98 × 10¹⁶ s^-1 and 4.39 × 10³⁴ s^-1, respectively.     

CH2(COO)2Cu·2H2O热分解的非等温动力学研究

The thermal dehydration and decomposition kinetics of CH₂(COO)₂Cu·2H₂O were investigated using the non-isothermal method by thermogravimetry (TG) technique in N₂. The iterative iso-conversional methods were applied to calculate the activation energy E_a of dehydration and decomposition， and the most probable mechanism function G(α) was determined by means of the master plots method. The pre-exponential factor A was obtained on the basis of E_a and G(α). Kinetic parameters (E_a and lnA) of dehydration were given as: E_a=139.79 kJ·mol^-1， ln(A/s^-1)=47.38. The mechanism function of the dehydration was G(α)=[-ln(1-α)]^2/3， and the decomposition of CH₂(COO)₂Cu proceeds to completion by two distinct reactions. These two reactions overlap in the transition process (0.45<α<0.65). Kinetic parameters (E_a and lnA )of the first reaction of decomposition were: E_a=201.15 kJ·mol^-1， ln(A/s^-1)=52.29， and the mechanism function was G(α)=[1-α]^-0.37. And in the second reaction G(α)=α+(1-α)ln(1-α)， E_a=156.74 kJ·mol^-1， ln(A/s^-1)=39.58.     

CH3CF2O2与HO2自由基反应机理的理论研究

用密度泛函理论(DFT)的B3LYP方法，在6-311G、6-311+G(d)、6-311++G(d, p) 基组水平上研究了CH₃CF₂O₂与HO₂自由基反应机理. 结果表明, CH3CF₂O₂与HO₂自由基反应存在两条可行的通道. 通道CH3CF₂O₂＋HO₂→IM1→TS1→CH₃CF₂OOH＋O₂的活化能为77.21 kJ•mol^－1，活化能较低，为主要反应通道，其产物是O₂和CH₃CF₂OOH. 这与实验结果是一致的；而通道CH₃CF₂O₂＋HO₂→IM2→TS2→IM3→TS3→IM4＋IM5→IM4＋TS4→IM4＋OH＋O₂→TS5＋OH＋O₂→CH₃＋CF₂O＋OH＋O₂→CH₃OH＋CF₂O＋O₂的控制步骤活化能为93.42 kJ•mol^－1，其产物是CH₃OH、CF₂O和O₂. 结果表明这条通道也能发生，这与前人的实验结果一致.     

一个含苯甲酸配体的Mn-Ce混合金属簇合物的合成、晶体结构与磁性研究

本文使用(NH₄)₂Ce(NO₃)₆氧化Mn2+法合成了1个结构新颖的Mn-Ce混合金属簇合物[Mn₃Ce₂(O)₅(O₂CPh)₉(CH₃OH)₃]·2CH₃CN(1·2CH₃CN, HO₂CPh代表苯甲酸), 并对其进行元素分析、红外光谱、单晶X-射线结构分析、磁性等表征。结构分析表明, 化合物1·2CH₃CN属于三斜晶系P1空间群, 结构中2个Mn⁴⁺离子、2个Ce⁴⁺离子和4个桥连μ₃-O原子组成1个不规则的立方烷, 然后通过另1个桥连μ₃-O原子与另1个Mn³⁺离子相连。晶胞内分子间没有氢键作用, 但存在较强的π-π堆积作用。磁性研究表明, 簇合物内Mn离子之间存在铁磁性耦合作用, 基态自旋值S=5和磁各向异性参数D=-0.31 cm^-1, 交流磁化率没有频率依赖现象。     

高岭石无定形化的动力学研究

Amorphous kaolinite derivatives were prepared through mixing kaolinite with HCOOK and KOH solution. Ki-netics of kaolinite being turned into amorphous derivatvies was investigated by XRD. It showed that the transfor-mation included dynamic and diffuse controlling stages. And the active energy E₁=26.8kJ·mol^-1; E₂=12.2 kJ·mol^-1. TEM and SEM images showed that particle size of the amorphous derivatives was about 50nm. And the amorphous derivatives seemed like alumnsilicate gel， accompanied by some aggregates.     

N，N-二丁基辛酰胺从硝酸介质中萃取铀(Ⅵ)和钍(Ⅳ)

合成了N,N-二丁基辛酰胺(简称DBOA)。以甲苯为稀释剂研究了DBOA萃取硝酸的平衡,认为低酸度下形成HNO₃·DBOA,得到萃取平衡常数为0.2 mol^-2·L²;研究了水相酸度和萃取剂浓度对DBOA萃取硝酸铀酰平衡的影响,得到萃合物组成UO₂(NO₃)₂·(DBOA)₂,25℃下萃取平衡常数为4.93 mol^-4·L⁴;利用红外光谱分析并确定了萃合物的结构;考察温度对萃取平衡的影响,得到萃取反应热为-29.1 kJ·mol^-1。实验结果表明相同条件下DBOA萃取Th⁴⁺、 Fe³⁺的能力很弱,UO²⁺₂能与之有效地分离,表明DBOA在钍-铀分离方面具有应用前景。     

水合偏硼酸钾的热化学研究

Hydrated potassium monoborate(KBO₂·4/3H₂O) was obtained from an aqueous solution in a mole ratio of K₂O∶B₂O₃=2∶1 and characterized by powder X-ray diffraction(XRD)， infrared spectroscopy(FT-IR) and Raman spectroscopy. The enthalpy of solution of hydrated potassium monoborate， KBO₂·4/3H₂O， in approximately 1mol·dm^-3 aqueous hydrochloric acid was determined. Together with the previously determined enthalpies of so-lution of H₃BO₃ in approximately 1mol·dm^-3 HCl(aq) ，and of KCl in aqueous(hydrochloric acid+boric acid)， the standard molar enthalpy of formation of -(1411.11±0.84)kJ·mol^-1 for KBO₂·4/3H₂O was obtained from the standard molar enthalpies of formation of KCl(s)， H₃BO₃(s)， and H₂O(l). The standard molar entropy of formation of -422.94J·K^-1·mol^-1 and standard molar entropy of 163.47J·K^-1·mol^-1 for KBO₂·4/3H₂O were calculated from the thermodynamic relations. A group contribution method is applicable to KBO₂·4/3H₂O.     

周期性密度泛函理论研究NO在Cu2O(111)表面上的吸附

运用广义梯度密度泛函理论(GGA)的PBE方法结合周期平板模型，在DND基组下，研究了NO以N端和O端两种吸附取向在Cu₂O(111)非极性表面上的吸附。通过对不同吸附位置的吸附能和几何构型参数的计算和比较发现：表面上配位不饱和的铜离子(CuCUS)为活性吸附位；NO的N端吸附比O端吸附更为有利，N端吸附时吸附能可达到113.5 kJ·mol^-1，而O端情况下只有39.7 kJ·mol^-1；NO倾斜吸附在Cu₂O(111)表面上，O端吸附时倾斜度更大。在两种吸附取向情况下，N-O键的伸缩振动频率都发生了较大的红移，N端吸附情况下红移150 cm^-1，O端时红移330 cm^-1。前线轨道分析表明，Cu与NO间的吸附作用主要是Cu的d轨道和NO的π^*轨道间的相互作用。表面弛豫的计算表明，Cu₂O(111)面的弛豫对O端吸附方式产生较大影响，考虑表面弛豫时O端吸附为很弱的化学吸附(吸附能为39.7 kJ·mol^-1)，而没有考虑弛豫时吸附能为60.5 kJ·mol^-1。     

蝎型铜配合物：Cu2[ μ-pz]2[HB(pz)3]2和Cu[B(pz)4]2的合成、结构及热分解动力学性质

本文设计合成了两种以聚吡唑硼酸盐、吡唑为配体的铜配合物Cu₂[ μ-pz]₂[HB(pz)₃]₂(1)和Cu[B(pz)₄]₂(2)(pz：吡唑(C₃H₄N₂))。运用元素分析、红外光谱对配合物进行了表征，并用X-ray衍射测定了它们的晶体结构。非等温热分解动力学研究表明：配合物1的热分解反应分两步，配合物2的热分解反应一步进行。通过计算，配合物1热分解的第一步反应的可能机理为成核与生长，n=1/4；第二步反应的可能机理为化学反应。其非等温动力学方程分别为：dα/dT=A/β e^-E/RT·1/4(1-α)[-ln(1-α)]^-3和dα/dT=A/β e^-E/RT·(1-α)²。分解反应的表观活化能分别是520.37 kJ·mol^-1和149.65 kJ·mol^-1；指前因子lnA分别是118.06 s^-1和28.10 s^-1。配合物2热分解的可能机理为化学反应。其非等温动力学方程为：dα/dT=A/β e^-E/RT·(1-α)²。分解反应的表观活化能是111.41 kJ·mol^-1；指前因子lnA是21.20 s^-1。     

Thermal Behavior of N,N＇Bis[N-（2,2,2-trinitroethyl）-N-nitro]ethylenediamine

The thermal behavior and kinetic parameters of the exothermic decomposition reaction of N‐N‐bis[N‐(2,2,2‐tri‐nitroethyl)‐N‐nitro]ethylenediamine in a temperature‐programmed mode have been investigated by means of differential scanning calorimetry (DSC). The results show that kinetic model function in differential form, apparent activation energy E_a and pre‐exponential factor A of this reaction are 3(1 ‐α)^2/3, 203.67 kJ·mol^?1 and 10^20.61s^?1, respectively. The critical temperature of thermal explosion of the compound is 182.2 °C. The values of ΔS^≠ ΔH^≠ and ΔG^≠ of this reaction are 143.3 J·mol^?1·K^?1, 199.5 kJ·mol^?1 and 135.5 kJ·mol^?1, respectively.     

Structures,Vibrational Spectra,and Relative Energetics of CH3COIO3 Isomers

The structures, vibrational spectra, relative energetics, and enthalpies of formation of CH₃COIO₃ isomers have been investigated with B3LYP, B3P86 and B3PW91 methods in conjugation with the 6‐31+G(d), 6‐311+G(d,p) and 6‐311++G(3df,3pd) basis sets. The CH₃COOIO₂ structure was found to be the most stable form among the isomers with an estimated enthalpy of formation of ?314.6 kJ·mol^?1. The enthalpies of formation for CH₃COOOOI, CH₃COOOIO and CH₃COIO₃ are ?180.7, ?184.9 and ?50.6 kJ·mol^?1, respectively. The implication of the formation of CH₃COIO₃ isomers from the atmospheric cross‐reactions of the acetylperoxy (CH₃COO₂) and iodine monoxide (IO) radicals was examined and the possible dissociation products of the most likely CH₃COIO₃ isomers were determined.     

Highly stable polyoxometalate‐resorcin[4]arene‐based inorganic‐organic complexes for catalytic oxidation desulfurization

Self‐assembly of a resorcin[4]arene‐based ligand (TMR4A) with metal salts and H₃PMo₁₂O₄₀·xH₂O offers two isostructural complexes, namely, [Ni₂Cl(TMR4A)₂(CH₃CN)₂]·[PMo₁₂O₄₀]·4CH₃CN ( 1 ) and [Co₂Cl(TMR4A)₂(CH₃CN)₂]·[PMo₁₂O₄₀]·4CH₃CN ( 2 ). In both 1 and 2 , one Cl^? anion bridges two metal cations, and each metal cation is further chelated by four 2‐mercaptopyridine N‐oxide groups of one TMR4A, producing a [M₂Cl(TMR4A)₂]³⁺ dimer (M = Ni or Co). The negative [PMo₁₂O₄₀]^3? as a counter‐anion balances the positive charge. Markedly, 1 and 2 exhibit high stability in aqueous solutions with different pH values and in organic solvents. Remarkably, the efficient heterogeneous catalytic capability for oxidative desulfurization was studied by suing 1 and 2 as recycled catalysts. Moreover, the electrochemical behaviors of the two compounds were discussed as well.     

4-硝基苯甲醇的低温热容和标准摩尔生成焓

用精密自动绝热量热计测定了4-硝基苯甲醇（4-NBA）在78 ~ 396 K温区的摩尔热容。其熔化温度、摩尔熔化焓及摩尔熔化熵分别为:(336.426 ± 0.088) K, (20.97 ± 0.13) kJ×mol-1 和 (57.24 ± 0.36) J×K-1×mol-1.根据热力学函数关系式,从热容值计算出了该物质在80 ~ 400 K温区的热力学函数值 [HT - H298.15 K] 和[ST - S298.15 K]. 用精密氧弹燃烧量热计测定了该物质在T＝298.15 K的恒容燃烧能和标准摩尔燃烧焓分别为 (C7H7NO3, s)＝- ( 3549.11 ± 1.47 ) kJ×mol-1 和 (C7H7NO3, s)＝- ( 3548.49 ± 1.47 ) kJ×mol-1. 利用标准摩尔燃烧焓和其他辅助热力学数据通过盖斯热化学循环, 计算出了该物质标准摩尔生成焓 (C7H7NO3, s)＝- (206.49 ± 2.52) kJ×mol-1 .     

Crystal Structure, Thermal Decomposition Behavior and the Standard Molar Enthalpy of Formation of a Novel 3D Hydrogen- Bonded Supramolecular [Co（HnicO）2·（H2O）2]

Hydrothermal synthesis and X-ray characterized 3D supramolecular networks were constructed by [Co（HnicO）2·（H2O）2] （HnicOH=2-hydroxynicofinic acid） （1） as building block via abundant dimeric homomeric （N--H…O） and unusually cyclic tetrameric heteromeric （O-H…O） hydrogen-bonds. It is noted that there exist unusually linear metal-water chains comprised of tetrameric units linked by vertexes sharing cobalt centers through hydrogen-bonding. TG-DTG curves illustrated that thermal decomposition was completed by two steps, one is the loss of two terminal water molecules in the range of 156--234℃, and the other is the pyrolysis of HnicO ligand in the range of 234--730 ℃. The standard molar enthalpy of formation of the complex was determined to be （-1845.43± 2.77） kJ·mol^-1 by a rotary-bomb combustion calorimeter.     

Phase Chemistry Investigation on Cr(NO3)3‐Met‐H2O System

The solubility property of the ternary of Cr(NO₃)₃‐Met‐H₂O has been investigated in the whole concentration by the phase equilibrium method, and the phase diagram has been constructed. From the phase diagram, the congruently soluble complexes Cr(Met)(NO₃)₃·2H₂O (D) and Cr(Met)₂(NO₃)₃·2H₂O (E) have been prepared and characterized by chemical analysis, elemental analysis, IR and TG‐DTG. Their combustion energies have been determined by a RBC‐type I precision rotating‐bomb calorimeter, and their standard enthalpies of formation, Δf, Hθ_m, have been calculated as (‐1842.01 ± 2.13) kJ·mol^?1 and (‐1136.16 ± 4.45) kJ·mol^?1, respectively.     

Thermal Behavior of 2‐(Dinitromethylene)‐1,3‐diazacyclopentane

A new compound, 2‐(dinitromethylene)‐1,3‐diazacyclopentane (DNDZ), was prepared by the reaction of 1,1‐diamino‐2,2‐dinitroethylene (FOX‐7) with 1,2‐diaminoethane in N‐methylpyrrolidone (NMP). Thermal decomposition of DNDZ was studied under non‐isothermal conditions by DSC, TG/DTG methods, and the enthalpy, apparent activation energy and pre‐exponential factor of the exothermic decomposition reaction were obtained as 317.13 kJ·mol^?1, 269.7 kJ·mol^?1 and 10^24.51 s^?1, respectively. The critical temperature of thermal explosion was 261.04°C. Specific heat capacity of DNDZ was determined with a micro‐DSC method and a theoretical calculation method, and the molar heat capacity was 205.41 J·mol^?1·K^?1 at 298.15 K. Adiabatic time‐to‐explosion was calculated to be a certain value between 263–289 s. DNDZ has higher thermal stability than FOX‐7.     

Kinetic Studies on the Reaction of Sodium Hexacyanoferrate（ll） Complex with Peroxydisulfate Anion

The oxidation of Na₄Fe(CN)₆ complex by S₂O anion was found to follow an outer‐sphere electron transfer mechanism. We firstly carried out the reaction at pH=1. The specific rate constants of the reaction, k_ox, are (8.1±0.07)×10^?2 and (4.3±0.1)×10^?2 mol^?1·L·s^?1 at μ=1.0 mol·L^?1 NaClO₄, T=298 K for pH=1 (0.1 mol·L^?1 HCl0₄) and 8, respectively. The activation parameters, obtained by measuring the rate constants of oxidation 283–303 K, were ΔH^≠=(69.0±5.6) kJ·mol^?1, ΔS^≠=(?0.34±0.041)×10² J·mol^?1·K^?1 at pH=l and ΔH^≠=(41.3±5.5) kJ·mol^?1, ΔS^≠=(?1.27±0.33)×10² J·mol^?1·K^?1 at pH=8, respectively. The cyclic voltammetry of Fe(CN) shows that the oxidation is a one‐electron reversible redox process with E_1/2 values of 0.55 and 0.46 V vs. normal hydrogen electrode at μ=1.0 mol·L^?1 LiClO₄, for pH=1 and pH=8 (Tris). respectively. The kinetic results were discussed on the basis of Marcus theory.     

Preparation and Thermal Chemical Property of Complexes of Zinc Nitrate with Trytophan

IntroductionZincisanessentialtraceelementtothelife .Manydiseasesarousedfromadeficiencyofzincelementhavere ceivedconsiderableattention .L α Aminoacidsarebasicunitsofproteins .L α Trytophanisoneoftheeightspeciesofaminoacidsindispensableforlife ,whichhastobeab sorbedfromfoodbecauseitcannotbesynthesizedinthehumanbody .InviewofthecomplexesofL α trytophanandessentialelementsasaddictiveswidelyusedinsuchfieldsasfoodstuff,medicineandcosmetic ,1 3theyhaveabroadenprospectforapplications .Briefly ,ab…     

1，1－二氨基2，2－二硝基乙烯（DADE）的热化学性质、热行为和热分解机理

The constant-volume combustion energy, △cU （DADE, s, 298.15 K）, the thermal behavior, and kinetics and mechanism of the exothermic decomposition reaction of 1,1-diamino-2,2-dinitroethylene （DADE） have been investigated by a precise rotating bomb calorimeter, TG-DTG, DSC, rapid-scan fourier transform infrared （RSFT-IR） spectroscopy and T-jump/FTIR, respectively. The value of △cHm （DADE, s, 298.15 K） was determined as （-8518.09±4.59） j·g^-1. Its standard enthalpy of combustion, △cU （DADE, s, 298.15 K）, and standard enthalpy of formation, △fHm （DADE, s, 298.15 K） were calculated to be （-1254.00±0.68） and （- 103.98±0.73） kJ·mol^-1, respectively The kinetic parameters （the apparent activation energy Ea and pre-exponential factor A） of the first exothermic decomposition reaction in a temperature-programmed mode obtained by Kissinger＇s method and Ozawa＇s method, were Ek=344.35 kJ·mol^-1, AR= 1034.50 S^-1 and Eo=335.32 kJ·mol^-1, respectively. The critical temperatures of thermal explosion of DADE were 206.98 and 207.08 ℃ by different methods. Information was obtained on its thermolysis detected by RSFT-IR and T-jump/FTIR.